Effect of operating conditions on direct liquefaction of low-lipid microalgae in ethanol-water co-solvent for bio-oil production. (1st June 2017)

• Record Type: Journal Article
• Authors: Ji, Changhao; He, Zhixia; Wang, Qian; Xu, Guisheng; Wang, Shuang; Xu, Zhixiang; Ji, Hengsong
• Is Part Of: Energy conversion and management. Volume 141(2017)
• Page Start: 155
• Page End: 162
• Publication Date: 2017-06-01
• Subjects: Direct liquefaction -- Microalgae -- Ethanol-water co-solvent -- Bio-oil; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2016.07.024
• Languages: English
• ISSNs: 0196-8904

Abstract

Graphical abstract: Highlights: Low-lipid microalgae was selected as feedstock for DL in ethanol-water co-solvent. Operating conditions had great influence on product yields and conversion rate. Bio-oil could be obtained from all three main components. Ethanol and water showed obviously synergistic effect during the DL of microalgae. Bio-oil composition from DL of microalgae was different from lignocellulose biomass. Abstract: In this work, the direct liquefaction (DL) of low-lipid microalgae Spirulina was investigated in a 50 ml autoclave reactor with ethanol and water as co-solvent. The objective of this research was carried out to examine the effect of operating conditions such as reaction temperature, reaction time, solvent/microalgae (S/M) ratio and ethanol-water co-solvent (EWCS) composition on product distribution and bio-oil characterization. The results revealed that the optimal operating conditions for bio-oil yield and conversion rate were reaction temperature of 300 °C, reaction time of 45 min, ethanol content of 50 vol.% and S/M ratio of 40/4 ml/g, which gave the bio-oil yield of 59.5% and conversion rate of 94.73%. Conversion rate in EWCS was significantly higher than that in pure water or ethanol, suggesting the synergistic effect between ethanol and water during microalgae DL. Distinct difference in composition and relative content of compound among bio-oils in different solvents were observed by GC–MS and FT-IR. Compared with hydrothermal liquefaction, the most abundant compounds in bio-oil from both EWCS and pure ethanol were esters. The presence of ethanol could enhance the bio-oil yield and improve bio-oil quality by promoting the formation of esters.